Pawl-and-ratchet mechanism.



C. F. DENNY.

PAWL AND RATCHET MECHANISM.

APPLICATION FILED JUNE H. 1915.

1,192,283. Patented July 25, 1916.

Ewuewtoz Witncaea COLUMBUS F. DENNY, OF DURHAM, NORTH CAROLINA.

PAWL-AND-RATCHET MECHANISM.

Specification of Letters Patent.

Patented July 25, 1916.

Application filed June 11, 1915. Serial No. 33,589.

To all whom it may concern:

Be it known that I, COLUMBUS F. DENNY, a citizen of the United States, residing at Durham, in the county of Durham and State of North Carolina, have invented new and useful Improvements in Pawl-and- Ratchet Mechanism, of which the following is a specification.

This invention relates to improvements in shade rollers and has relation more particularly to an improved novel pawl and ratchet construction therefor, and the object of the same is to provide a device of this character wherein the pawl is automatically raised to free the same from contact with the teeth of the ratchet wheel and permitting of the shade being readily wound on the roller through the action of its spring, and without creating a noise.

The invention further consists of an improved form of pawl provided with a doubled tooth adapted to engage both with the pawl operating gear and the ratchet wheel.

A further object of the invention is the provision of a novel pawl operating gear, wherein the teeth thereof are interrupted to form the pawl operating device with a plurality of spaced cams, said cams being disposed at a farther distance from the axis of the gear than are the uninterrupted teeth of suchgear.

The invention consists in the novel features, details of construction and combination of parts which will hereinafter be more fully" set forth, illustrated in the accompanying drawing and pointed out in the appended claims. 7

In the accompanying drawing :Figure1 is a longitudinal section of the shade roller, illustrating the improved pawl and ratchet mechanism attached thereto. Fig. 2 is an end view. Fig. 3 is a perspective view of the locking pawl. Fig. 4 is an enlarged side elevation of the pawl operating gear.

Corresponding and like parts are referred to in the following description and indicated in all the views of the drawing by the same reference characters.

Referring more particularly to the draw ing, 5 denotes the shade roller, including a hollow cylindrical metallic casing 6, rotatably mounted on the shaft or arbor 7. A 0011 spring 8 is disposed within the casing 6 and encircles the shaft 7, the said spring closed by means of disks 11 and 12.

Mounted upon the pintle 12 of the shaft 7 is a noiseless spring winding mechanism 13, including a ratchet wheel 14 and a pawl operating gear 15. The pawl operating gear 15 being disposed on the pintle 12 of the shaft, and frictionally engaging with said pintle and at a point inwardly of the said ratchet wheel 14 and abutting with the adjacent end wall or disk 12 of the casing. It will of course be apparent that this mechanism may be fixed to the pintle 12 in any desired manner.

As previously stated, the pawl operating gear 15 is frictionally mounted on a pintle 12 in such a manner as to prevent any accidental rotation thereof upon said pintle and the ratchet wheel 14 is stationarily mounted on said pintle and in juxtaposition to the pawl operating gear. The said ratchet wheel 14 is formed on its peripheral edge with a series of uninterrupted teeth 16.

The pawl operating gear 15 is provided on its peripheral edge with a series of teeth 17, mutilated at predetermined intervals to form the pawl operating gear, with a plurality of concentrically disposed enlarged cam-shaped toothed portions 18. The teeth of the said cam-shaped portions are disposed at an angle to a radial line for a purpose which will be hereinafter set forth.

Pivotally mounted on the exterior surface of the end disk 12 of the casing, at a point above the cam-shaped portions 18, is a ratchet pawl 19. The said pawl having its free or active terminal thickened to form the pawl with a doubled toothed portion 20 and 21. The tooth 2001" the pawl being of lesser length than its tooth 21. The tooth 20 is formed with a downwardly and forwardly beveled face 22 adapted to engage with the teeth of the pawl operating gear at all times by means of the spring .19. In

view of the fact that the ratchet wheel 14 is of lesser diameter than the diameter of the series of cam-shaped toothed portions 18, of the pawl operating gear 15, and the tooth 21 of the ratchet, by being of a length greater than the length of the tooth 20 thereof, will permit the tooth 21 to straddle the camshaped portions exteriorly, and extend downwardly and into engagement therewith and adapted to operate with the teeth of the ratchet wheel. The tooth 21 is retained in engagement with the said ratchet wheel, by means of the spring 19. I

It is to be further stated and for a more clear understanding of the operation of the device, that when it is desired to throw the tooth 22 out of engagement with the teeth of the ratchet 14, to permit of, for the purpose of illustration, the winding up of the shadeupon theroller or casement 5, the camshaped portions 18 contact with the shorter tooth 20 of the ratchetpawl 19 and readily lift the same out of engagement withthe ratchet teeth and against the tension of its spring 19.

From the foregoing description, it will be apparent to those skilled in the art to which the invention relates, that when a pull is given the window shade causes the rotation of its roller 5, which inturn tensions the spring 8 and causes the tooth 20 to be brought into engagement with the teeth 17 of the cam operating gear whereby the cam shaped gears 18 lift the tooth 21 of the pawl 19 from engagement with the teeth 16 of the ratchet wheel 14, which operation permits of the shade being speedily wound upon its roller or casing.

Even though I have illustratedland described this specific type of pawl and ratchet mechanism used in connection with a win dow-shade roller, it is to be understood that I do not limit myself to the use of such pawl and ratchet mechanism to this specific type of invention, as I have found by the practical use of the same that this form of pawl and rachet mechanism is advantageous to other devices, reference being had more particularly to eye-glass reels.

From the foregoing description, taken in connection with the accompanying drawing, the advantages of construction and of the method of operation will be readily apparent to those skilled in the art to which the invention relates. lVhileI have described the principles of operation of the device to- I gether with the device which I now consider to be the best embodiment thereof, I desire to have it understood. that the device shown is merely illustrative and that such advan-o tages may be made when desired as are thereto.

What is claimed as new is z- I 1. In a ratchet mechanism, a rotatable element, a ratchet wheel stationarily supported relative to said element, a' ratchet pawl carried by the said elementand normally held in workingengagement with the ratchet, and a ratchet pawl lifting member mounted in juxtaposition to the ratchet wheel, said ratchet pawl lifting member being provided with a series of concentrically spaced interrupted ratchet teeth, the said interrupted ratchet teeth of the ratchet pawl lifting member engaging with the ratchet ratchet pawl lifting member being provided with a series of concentrically spaced interrupted ratchet teeth, the said interrupted ratchet teeth of the ratchet pawl lifting member engaging with the ratchet pawl for intermittently releasing the ratchet pawl from the ratchet wheel, and means for holding the pawl in positive engagement with the ratchet, wheel.

' 3. Ina ratchet mechanism, a rotatable element, a ratchet wheel stationarily supported relative to said element, a ratchet pawl carried by the 'said element and normally held in working engagement with the ratchet, and a ratchet pawl lifting member mounted in juxtaposition to the ratchet wheel, said ratchet pawl lifting member being provided with a series of concentrically spaced interrupted ratchet teeth, the" said interrupted ratchet teeth of the ratchet pawl lifting member engaging with the ratchet pawl for intermittently releasing the ratchet pawl from the ratchet wheel, means for holding the pawl in positive engagement with the ratchet wheel, and the said ratchet pawl lifting member.

4. In a ratchet mechanism, a rotatable element, a ratchet wheel stationarily supported relative to said element, a doubletoothed ratchet pawl carried by the said element and normally held in working engage ment with the ratchet, and a ratchet pawl lifting member mounted in juxtaposition to the ratchet wheel for intermittently releasing the ratchet pawl from the latter.

5. In a ratchet mechanism, a rotatable iio iis

element, a ratchet wheel stationarily sup-" ported relative to said element, a double toothed ratchet pawl carried by the said element and normally held in working engagement with the ratchet, a ratchet pawl lifting member mounted in juxtaposition t0 the ratchet Wheel for intermittently releasing the ratchet pawl from the latter, and means for holding one tooth of the pawl in positive engagement With the ratchet wheel and In testimony whereof I afiix my signature in presence of tWo Witnesses.

COLUMBUS F. DENNY.

the other tooth of the pawl in positive en- Witnesses: gagement With the said ratchet pawl lifting R. L. FLETCHER, member. A. L. WILGOX.

Copies of this patent may be obtained for five cents each, by addressing the Gommissioner of Patents. Washington, D. 0. 

